1. Field of the Invention
The present invention relates to an indicating device for menstruation, and more particularly to an indicating device that uses a mathematical method containing weighting coefficients to estimate user's monthly gynecophysiological factors.
2. Description of the Prior Art
Ovulation prediction is important both from the view point of contraception and enhancing fertility.
In respect to enhancing fertility, a woman who wishes to become pregnant has two main alternatives. She can take ovulation-enhancing drugs that have significant side effects; or she can predict the time of ovulation and intercourse at that time for the purpose of conception. One method of detecting and timing ovulation that is simple and well known is recording the basal body temperatures (BBTs) when a woman is waking at morning. This method is based on the fact that a rise in temperature indicates that ovulation has occurred.
The problems with the BBT method are illustrated as follows. The reliability of the BBT method is doubtful, because its effectiveness depends on how accurately the temperature is measured, how carefully the temperature is recorded, and how well this temperature correlates with the actual time of ovulation. This is because only a small rise (about 0.3 to 0.5.degree. C.) occurs in the BBT at the time of ovulation, so an inaccurate value may be obtained unless the measurement and the recording are performed carefully. Moreover, a rise in the BBT dose not always indicate an occurrence of ovulation, for example an infected inflammation will cause a small rise in the BBT. In addition, for a woman desiring to become pregnant, indicia for fertility status (a rise in the BBT) does not occur until the peak time of fertility is almost over.
Some researchers believe that the best fertile time of an ovum may not be more than 12 hours. However, spermatozoa are thought to be viable up to 72 hours in the female genital tract. For a woman desiring to become pregnant, it definitely would be advantageous to know several days ahead when ovulation will occur.
On the other hand, contraception is needed for a woman who does not want to become pregnant. Various natural methods of contraception are referred to as the safe period, this method usually requires that couples abstain from intercourse for at least eight days approximately at midcycle between the menses. It is thought that the ovum released from the ovary is susceptible to fertilization for only 12 hours; and that the spermatozoa deposited in the female reproductive tract are capable of fertilizing the ovum for only 72 hours. Thus, if intercourse did not occur just before and during this period, the spermatozoa could not fertilize the ovum and conception could not take place. This in theory, is a safe and simple method of contraception.
However, in practice, the safe period method has some difficulties. If a woman has regular menstrual cycles, then this method is reliable, because she can readily know from the calendar the safe days after and before ovulation and restrict intercourse accordingly. But menstrual and/or ovulation cycles in many women are often irregular, for example, the menstrual cycle may vary as long as 7 to 13 days for the peak reproductive years and by even greater margins for girls in their teens and women approaching menopause. It is not completely reliable to predict the ovulation time by simply estimating from the estimated next menstrual commence day.
Besides, contraceptive methods also include the BBT method. The BBT method as mentioned above has one drawback that its reliability depends on several factors. In addition, this method has another drawback that it cannot predict in advance when ovulation will take place. Thus the BBT method of contraception is effective after ovulation and so abstinence is required for about two weeks out of each menstrual cycle.
Further, conventional methods of measuring the BBTs are to measure the axillary, oral, vaginal, or rectal temperature by using a mercury or an electronic thermometer; in which the vaginal temperature or the rectal temperature are more representative of the real body temperature, but their measurements are inconvenient; the axillary temperature or the oral temperature can be conveniently measured, but their accuracy is influenced by the possibility of differences in measuring positions and measuring time intervals. In addition, frequent measurements of body temperatures are required in the BBT method, and the temperature detection must be conducted for more than 5 minutes, thus making it very inconvenient to use.